U.S. patent number 5,124,864 [Application Number 07/517,746] was granted by the patent office on 1992-06-23 for magnetic head supporting device including a flexible member of polymeric resinous material.
This patent grant is currently assigned to TDK Corporation. Invention is credited to Mikio Matsuzaki.
United States Patent |
5,124,864 |
Matsuzaki |
* June 23, 1992 |
Magnetic head supporting device including a flexible member of
polymeric resinous material
Abstract
A magnetic head supporting device for supporting a magnetic head
comprises a flexible member, a magnetic head supporting arm and a
magnetic head pressing arm, wherein the flexible member is a
plate-like body made of a polymeric resinous material, the magnetic
head supporting arm is a pair of supporting arms being spaced apart
from each other and attached to the flexible member, and the
magnetic head pressing arm is attached to the flexible member and
has an end portion extending between the pair of supporting
arms.
Inventors: |
Matsuzaki; Mikio (Tokyo,
JP) |
Assignee: |
TDK Corporation (Tokyo,
JP)
|
[*] Notice: |
The portion of the term of this patent
subsequent to March 19, 2008 has been disclaimed. |
Family
ID: |
14606619 |
Appl.
No.: |
07/517,746 |
Filed: |
May 2, 1990 |
Foreign Application Priority Data
|
|
|
|
|
May 3, 1989 [JP] |
|
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1-113220 |
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Current U.S.
Class: |
360/244.4;
360/245.5; G9B/5.152 |
Current CPC
Class: |
G11B
5/4853 (20130101) |
Current International
Class: |
G11B
5/48 (20060101); G11B 005/60 (); G11B 005/49 ();
G11B 021/16 (); G11B 021/21 () |
Field of
Search: |
;360/103,104 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tupper; Robert S.
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt
Claims
What is claimed is:
1. A magnetic head supporting device for supporting a magnetic
head, said supporting device comprising:
a flexible member;
a pair of magnetic head supporting arms for supporting the magnetic
head, said magnetic head supporting arms being spaced apart from
each other and attached to the flexible member; and
a magnetic head pressing arm attached to the flexible member and
having an end portion extending between said pair of supporting
arms for contacting said magnetic head, wherein the flexible member
is a plate-like body made of a polymeric resinous material.
2. The magnetic head supporting device according to claim 1,
wherein the pair of magnetic head supporting arms extend in
parallel to the each other and in the longitudinal direction of the
flexible member.
3. The magnetic head supporting device according to claim 1,
wherein the pair of magnetic head supporting arms extend in
parallel to each other and in the direction perpendicular to the
longitudinal direction of the flexible member.
4. The magnetic head supporting device according to claim 1,
wherein an opening is formed at an end portion in the longitudinal
direction of the flexible member; the pair of magnetic head
supporting arms extend across the opening, and the free end of the
magnetic head pressing arm terminates at a central portion of the
opening.
Description
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention relates to a magnetic head supporting device
for supporting a magnetic head, especially, a small-sized thin film
magnetic head.
2. DISCUSSION OF BACKGROUND
In the magnetic head supporting device of this type, the following
requirements have to be satisfied in order that the thin film
magnetic head can follow tracks formed in a surface of the magnetic
disk with a predetermined small gap. Namely, a slider of the
magnetic head which holds reading/writing elements undergoes a
pitching motion with respect to a first axis and a rolling motion
with respect to a second axis which perpendicularly intersects the
first axis to thereby remove uneven swinging motions. Such magnetic
head supporting device is disclosed, for instance, in U.S. Pat. No.
393164 and U.S. Pat. No. 4167765.
The conventional magnetic head supporting device disclosed in the
above-mentioned publications is generally constructed as follows. A
supporter comprising a resilient spring portion and a rigid beam
portion formed integrally with the resilient spring portion is
formed of a resilient metal plate such as a stainless steel plate.
A flexible member formed also of a resilient metal plate such as
stainless steel is attached to a free end of the supporter. A
loading projection is provided either on the upper surface of the
flexible member or on the lower surface of the supporter at a
position near the free end so that a load is applied from the free
end of the supporter to the flexible member. Then, a thin film
magnetic head which holds a slider having reading/writing elements,
is attached to the lower surface of the flexible member.
The magnetic head supporting device of this kind has a tendency
that the size of a magnetic head is reduced in order to comply with
demands of high density magnetic recording and quick recording. The
miniaturization of the magnetic head is effective to reduce a
flying height and a spacing loss which are necessary to achieve
high density recording as well as to increase resonance frequency;
to prevent crashing and to improve durability in association with a
magnetic head supporter. Further, the miniaturization of the
magnetic head facilitates the maintenance of an appropriate balance
between a dynamic pressure and a spring pressure by the supporter,
a good floating posture and the obtaining of stable floating
characteristic. Furthermore, by reducing the mass of the magnetic
head by the miniaturization allows the accessing movement at a high
speed.
In the conventional magnetic head supporting device, there were the
following problems.
(1) In order to obtain a magnetic head supporting device which
effects a low flying height, it is necessary to reduce a dynamic
pressure for lifting the magnetic head by reducing the surface area
of the air bearing surface of a slider which is a part of the
magnetic head. Since the conventional magnetic head supporting
device comprises a flexible member constituted by a resilient
metallic plate of a material such as stainless steel, the spring
function of the flexible member is far stronger than the dynamic
pressure for lifting the magnetic head which is produced at the
slider, so that when a low flying height is to be obtained, it is
difficult to balance the spring function to the dynamic pressure,
and it is difficult to obtain a stable control of the posture of
the magnetic head.
(2) In order to obtain good balance between the spring function of
the flexible member and the dynamic pressure, it is necessary that
the flexible member has a complicated shape and structure as
described in the above-mentioned publications. However, since the
flexible member is made of a resilient metallic plate such as
stainless steel, it is difficult for the flexible member to have a
complicated structure. In particular, when the size of the slider
which is the major part of the magnetic head is made small, in
order to achieve a low flying height, the size of the flexible
member should also be reduced. Accordingly, the processing of the
flexible member is also difficult.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a magnetic head
supporting device having a simple structure, supporting a
small-sized magnetic head, assuring an appropriate balance between
a dynamic pressure and the spring pressure to thereby assure good
posture of floating and stable floating characteristic, and capable
of recording at a high density and effecting a accessing movement
at a high speed.
The foregoing and other objects of the present invention have been
attained by providing a magnetic head supporting device for
supporting a magnetic head which comprises a flexible member, a
magnetic head supporting arm and a magnetic head pressing arm,
wherein the flexible member is a plate-like body made of a
polymeric resinous material, the magnetic head supporting arm is a
pair of supporting arms being spaced apart from each other and
attached to the flexible member, and the magnetic head pressing arm
is attached to the flexible member and has an end portion extending
between the pair of supporting arms.
BRIEF DESCRIPTION OF DRAWINGS
A more complete appreciation of the invention and many of the
attendant advantages thereof will be readily obtained as the same
becomes better understood by reference to the following detailed
description when considered in connection with the accompanying
drawings, wherein:
FIG. 1 is a perspective view of an embodiment of the magnetic head
supporting device according to the present invention;
FIG. 2 is a perspective view of another embodiment of the magnetic
head supporting device according to the present invention;
FIG. 3 is a cross-sectional view taken along a line A1--A1 in FIG.
1;
FIG. 4 is a cross-sectional view taken along a line A2--A2 in FIG.
1;
FIG. 5 is a cross-sectional view similar to FIG. 4 of another
embodiment of the magnetic head supporting device of the present
invention;
FIG. 6 is a perspective view showing a combination of the magnetic
head supporting device shown in FIG. 1 and a thin film magnetic
head;
FIG. 7 is a perspective view showing a combination of the magnetic
head supporting device shown in FIG. 2 and thin film magnetic
head;
FIG. 8 is a cross-sectional view of an important portion of the
combination shown in FIG. 6;
FIG. 9 is a cross-sectional view of an important portion of the
combination shown in FIG. 7;
FIG. 10 is a plane view showing a relation of the magnetic head
supporting device of the present invention which is shown in FIG. 1
to a magnetic disk;
FIG. 11 is a plane view showing a relation of the magnetic head
supporting device shown in FIG. 2 to a magnetic disk;
FIG. 12 is a perspective view of a thin film magnetic head which is
suitably assembled to the magnetic head supporting device of the
present invention; and
FIG. 13 is a perspective view of a reading/writing element in the
thin film magnetic head shown in FIG. 12.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to the drawings, wherein the same reference numerals
designate the same or corresponding parts throughout the several
views, and more particularly to FIG. 1 thereof, there is shown in
perspective view an embodiment of the magnetic head supporting
device according to the present invention. In FIG. 1, a reference
numeral 1 designates a flexible member, numerals 2 and 3 designate
magnetic head supporting arms, a numeral 4 designates a magnetic
head pressing arm and a numeral 5 designates a fitting piece.
The flexible member 1 is formed in a plate-like shape by using a
polymeric resinous material as an insulating material. As a
polymeric material used for the flexible member, such a material,
e.g. polyimide resin as that having a mechanical strength durable
to repeated bending operations and twisting operations and showing
an appropriate spring function and elongation is suitable. At one
side of the flexible member 1, there is provided an opening 101
where the thin film magnetic head is placed. Thus, by forming the
flexible member 1 by a polymeric resinous material, the flexible
member 1 shows a weak spring function and a high degree of freedom
of twisting and elongation in comparison with the conventional
flexible member made of a resilient metallic material such as
stainless steel. Accordingly, even in a case that the size of the
magnetic head is reduced to reduce a flying height in order to
obtain high density magnetic recording, there is still obtainable a
balance between the dynamic pressure produced at the slider and the
spring function of the flexible member 1, and therefore, a stable
control of the posture of the magnetic head can be obtained.
Further, the flexible member 1 made of a polymeric resinous
material allows easy processing.
As shown in FIG. 3, the magnetic head supporting arms 2, 3 are
embedded in the flexible member 1. Especially, each one end of the
supporting arms 2, 3 is apart from each other in a parallel
relation in the opening 101. In this embodiment, the supporting
arms 2, 3 are formed of an electric conductive material.
Accordingly, they function as lead wires for the magnetic head.
Each other end 21, 31 is led outside the flexible member 1 so that
the other ends are connected to the magnetic disk drive.
A fitting piece 5 made of a rigid material such as metal is
integrally attached to the other end of the flexible member 1 by
means of bonding. The magnetic head pressure arm 4 extends from the
fitting piece 5 through the upper surface of the flexible member 1
to an area of the opening 101 so that the free end 41 of the
pressure arm 4 terminates a position between the magnetic head
supporting arms 2, 3 which are exposed in the opening 101.
The magnetic head pressure arm 4 may be independent from the
fitting piece 5 so that the pressing arm 4 is separately attached
to the flexible member 1. The free end portion 41 of the magnetic
head pressing arm 4 may have a projection as shown in FIG. 4, or
may have a circular shape in cross section as shown in FIG. 5.
Further, it may have a rectangular shape in cross section although
not shown in drawing.
FIG. 2 shows another embodiment of the magnetic head supporting
device according to the present invention. In this embodiment, a
pair of magnetic head supporting arms 2, 3 are arranged in parallel
to each other and in the direction perpendicular to the
longitudinal direction of the flexible member 1. The other
construction of this embodiment is the same as the embodiment as
shown in FIG. 1.
The shape and construction of the magnetic head to be held by the
magnetic head supporting device of the present invention is not
particularly limited, and a well-known magnetic head or any
magnetic head which will be proposed can be used.
FIG. 6 shows an example of a combination of the magnetic head
supporting device as shown in FIG. 1 and a thin film magnetic head,
and FIG. 7 shows an example of a combination of the magnetic head
supporting device as shown in FIG. 2 and a thin film magnetic head.
In FIGS. 6 and 7, a reference numeral 6 designates a thin film
magnetic head in which a thin film reading/writing element 62 is
attached to an end surface of a slider 61.
In the combination of the magnetic head supporting device and the
magnetic head 6, the magnetic head supporting arms 2, 3 are
respectively attached to opposing side surfaces 611, 612 of the
slider 61 by means of bonding. The free end portion 41 of the
pressing arm 41 is brought to contact with the upper surface 613 of
the slider 61. The free end 41 of the magnetic head pressing arm 4
is in spring-contact with the upper surface 613 of the slider 61 so
that the thin film magnetic head 6 receives a load from the
pressing arm 4 downwardly.
FIG. 6 shows the thin film magnetic head 6 which is oriented along
the longitudinal direction of the flexible member 1. FIG. 7 shows
the thin film magnetic head 6 which is oriented in the direction
perpendicular to the longitudinal direction of the flexible member
1. A numeral 614 designates an air bearing surface.
In a case that the free end portion 41 of the magnetic head
pressing arm 4 has a projection as shown in FIG. 4, the contact of
the projection 41 to the upper surface 613 of the slider 41 is of a
point contact type as shown in FIG. 8. On the other hand, in a case
that it has a projection having a circular form in cross section as
shown in FIG. 5, the contact of the projection is of a line contact
as shown in FIG. 9.
FIG. 10 is a plane view showing a relation of the magnetic head
supporting device of the present invention as shown in FIG. 1 to a
magnetic disk, wherein a numeral 7 designates the magnetic disk, a
numeral 8 designates the magnetic head supporting device of the
present invention and a numeral 9 designates a position determining
unit. The magnetic disk 7 is driven to rotate in the direction
indicated by an arrow mark a by means of a rotation driving unit
(not shown). The magnetic head supporting device 8 is driven by the
position determining unit 9 so that the thin film magnetic head 5
performs a turning movement on the diameter O.sub.1 of the magnetic
disk 7 in the direction indicated by an arrow mark b.sub.1 or
b.sub.2. Thus, reading operations or writing operations can be
attained on a track in the magnetic disk 7.
FIG. 11 is a plane view showing a positional relation of the
magnetic head supporting device as shown in FIG. 2 to a magnetic
disk. In FIG. 11, the thin film magnetic head 6 of the magnetic
disk 7 is linearly moved on the diameter O.sub.1 in the direction
of an arrow mark b.sub.1 or b.sub.2.
An embodiment of the thin film magnetic head which is suitable for
being combined with the magnetic head supporting device of the
present invention will be described. FIG. 12 is an enlarged
perspective view of the thin film magnetic head. An air bearing
surface 614 is formed in a slider 61 so as to oppose a magnetic
recording medium. The air bearing surface 614 is made flat without
having rail portions and taper portions which produce a lifting
force. It is preferable that edges A, B formed at the air bearing
surface, which are respectively the air-inflow end and the air
discharge end, are respectively in a form of an arc so that the
dragging of the slider 61 to the surface of a magnetic disk at the
time of contact-start can be eliminated. Other edges C, D may be in
a form of an arc.
The slider 61 comprises a substrate of Al.sub.2 O.sub.3
.multidot.TiC on which an insulating film 110 of a material such as
alumina or the like is coated, and the reading/writing element 62
is formed on the insulating film.
A reading/writing element 62 is formed in an end surface which is
provided at the side of air-discharging with respect to an air flow
flowing in association with the magnetic recording medium. In this
embodiment, a single reading/writing element 62 is used, and the
element is arranged at an intermediate portion in the direction of
width of the slider 61.
Bonding pads 621, 622 for the reading/writing element 62 are
introduced to opposing side surfaces 611, 612 of the slider 61.
Further, grooves 63, 64 in a form of stripe are formed in the
opposing side surfaces 611, 612 of the slider 61 in its entire
length so as to extend through the bonding pads 63, 64.
FIG. 13 is a perspective view showing the construction of the
reading/writing element 62. In FIG. 13, a reference numeral 623
designates a lower magnetic film, a numeral 624 designates a gap
film made of a material such as alumina, a numeral 625 designates
an upper magnetic film, a numeral 626 designates conductor coil
films, a numeral 627 designates an insulating film made of an
organic resinous material such as novolak resin, and numerals 628,
629 designate lead electrodes.
Each end portion of the lower and upper magnetic films 623, 625
constitute a pole section which opposes each other with the gap
film 624 having a small thickness. The pole sections perform
reading and writing function. The lower magnetic film 623 is
connected with the upper magnetic film 625 at the position opposite
the pole sections. The conductor coil films 626 are formed so as to
surround around the connecting portion in a spiral form.
The lead electrodes 628, 629 have their one ends connected to both
ends of the conductor coil films 626 and other ends connected to
the bonding pads 621, 622.
The bonding pads 621, 622 are exposed at the opposing side surfaces
611, 612 of the slider 61. The bonding pads 621, 622 are formed as
plated films so that the surface areas exposed at the opposing side
surfaces 611, 612 have a sufficient surface areas necessary to
connect the lead wires. Specifically, each of the surface areas has
a width d.sub.1 of about 100-250 .mu.m and a height h.sub.1 of
about 50 .mu.m.
The bonding pads 621, 622 are covered by a protective film 630. In
the conventional magnetic head, it was necessary to polish the
surface of the protective film 630 to thereby expose the electrode
surfaces of the bonding pads so as to bond the lead wires. In the
present invention, however, such polishing work is unnecessary to
thereby simplified manufacturing steps.
In the combination of the magnetic head with the magnetic head
supporting device, the magnetic head 6 is placed between the
supporting arms 2, 3 in the opening 101, each of the supporting
arms 2, 3 is connected to each of the opposing side surfaces of the
magnetic head 6, and the supporting arms 2, 3 are respectively
connected to the bonding pads 621, 622 exposed at the opposing
surfaces, by means of soldering.
In this embodiment, grooves 63, 64 are formed in a stripe in the
opposing side surfaces 611, 612 of the slider 61 over the entire
length of the slider, the grooves being communicated with the
bonding pads 621, 622, whereby the supporting arms 2, 3 can be
placed correctly in position in the grooves 63, 64 and they are
connected to the bonding pads 621, 622. Accordingly, reliability in
determining the position of the magnetic head 6 to the supporting
arms 2, 3 and the connection in electrical and mechanical sense of
the former to the later can be improved.
Since the bonding pads 621 or 622 for the reading/writing element
62 are formed in the opposing side surfaces 611, 612 of the slider
61, the width of an end surface where the reading/writing element
62 is formed can be reduced to thereby reduce the surface area of
the end surface, whereby the entire size of the thin film magnetic
head can be reduced unlike the conventional technique wherein the
bonding pads 621, 622 are formed in the same end surface where the
reading/writing element 62 is formed. Specifically, the size of the
slider 61 can be reduced in such a manner that the thickness from
the air bearing surface 614 to the opposing upper surface is 0.66
mm or less, the length in the direction of air flow is in a range
of 0.6 mm-2 mm and the width in the direction perpendicular to the
direction of air flow is in a range of about 0.6 mm-2 mm.
Further, in the above-mentioned small-sized magnetic head, since
grooves 63, 64 are formed, the magnetic head supporting arms 2,3
which also serve as lead wires can be fitted to the grooves 63, 64
and they can be certainly and stably connected to the bonding pads
621, 622.
Further, since a cut surface of a wafer when the wafer is cut to
obtain separate thin film magnetic heads in manufacturing steps is
utilized as the side surface 611 or 612 on which the bonding pad or
pads 621, 622 are to be introduced, the bonding pads 621, 622 can
be exposed at the side surface 611 or 612 as soon as the cutting
operation has finished.
In the above-mentioned embodiment, explanation is made as to use of
an in-plane recording and reproducing thin film magnetic head.
However, the present invention is applicable to a vertical magnetic
recording and reproducing thin film magnetic head. Further, the
present invention is applicable to a thin film magnetic produce a
floating force in the air bearing surface.
Thus, in accordance with the present invention, the following
effects can be obtained.
(a) The flexible member made of the polymeric resinous material has
a high degree of freedom of twisting and elongation. Accordingly,
there is obtainable a magnetic head supporting device which assures
the balance between the dynamic pressure for floating on the slider
and the elasticity of the flexible member and stable posture of the
magnetic head even when the magnetic head is miniaturized to
thereby reduce a flying height and to increase the density of the
magnetic recording.
(b) Since the flexible member is formed by a polymeric resinous
material, the flexible member can be easily machined and
assembled.
(c) A pair of the magnetic head supporting arms which are spaced
apart from each other in a parallel relation are attached to the
flexible member, and the magnetic head pressing arm is attached to
the flexible member so that an end of the pressing arm terminates
between the supporting arms, whereby the construction of the
magnetic head supporting device of the present invention is simple
while there are obtainable a pitching motion, a rolling motion and
a loading action which are required for magnetically recording and
reproducing to a magnetic disk.
Obviously, numerous modifications and variations of the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
* * * * *